BY JENNIFER BABSON

  Twenty Cuban migrants, spotted by a passing boater on an island in Biscayne National Park early Tuesday, probably were smuggled, a U.S. Border Patrol spokesman said.

  The 15 men and five women appeared to be in good condition when they were found on Boca Chita Key at 8:30 a.m., said Anastasia Burns, a Miami-based spokeswoman for the U.S. Coast Guard.

  The migrants did not physically appear to have been at sea for long and there was no boat at their landing site, leading investigators to believe they were probably
  transported clandestinely from Cuba by professionals, said Thomas Rockwood, a Border Patrol spokesman. ''It was probably a smuggling load,'' he said.

  Located in the northern part of the park, Boca Chita is a popular spot that includes a campground and a 65-foot lighthouse.

  In initial interviews, the migrants -- who were taken to the Border Patrol's Pembroke Pines processing facility -- said they departed from Villa Clara province on Cuba's north coast.

  The group was expected to be moved to Krome Detention Center in West Miami-Dade, then released into the custody of friends and relatives.

  Under U.S. immigration policy, Cubans who reach U.S. shores are allowed to stay, while those who are intercepted at sea by authorities are generally returned.

  Rockwood said fewer Cuban migrants have been smuggled to the Keys this spring and early summer than during the same time period in previous years. In the past, smuggling has typically increased in the warmer months, when smooth seas make for a calmer crossing. ''There have only been a handful of actual landings, and those have been mostly rafters,'' Rockwood said.

  The recent downturn in smuggling follows a crackdown by the Cuban government on dissidents and others, and the execution in April of three armed Cuban men who hijacked a Cuban passenger ferry in attempt to reach Florida.